The protector over the chain wheels looks very CPSC-ish to me. So I was thinking much later than the others; not 50's or 60's but early 70's. The other components seem to agree but many/most could have been replaced over time. Most components are at risk for replacement but the crank is usually the last to go. Replacing an old steel crank with a newer steel crank does not sound likely to me.

Those bars and stem are awesome!